Single pin fluorescent lamps are known and have been constructed with a variety of diameters; e.g., T6, T8, T12 (T1=1/8"). In the smaller sizes, notably T8 and below, it has been necessary to fabricate the bases of plastic or other electrically insulating material to avoid having the emitter electrode wires come in contact with the base and cause a short circuit. This problem did not exist in the T12 sizes, which were made with an electrically conductive base having an insulating center portion fixed therein. The larger diameter of the T12 lamp provided insurance against the electrode wires coming into contact with the electrically conductive base. The use of electrically conductive bases is highly advantageous because of strength and ease of making. Also, such bases are less expensive.